1. Field of Invention
The present invention relates generally to the field of optical lithography. More specifically, the present invention is related to resolution enhancement in optical lithography via absorbance modulation.
2. Discussion of Prior Art
The following references provide general background in the area of optical lithography, but none of them, either by themselves or in combination, teaches or suggests the features of the present invention.
The U.S. patent to Case et al. U.S. Pat. No. 6,879,376 teaches a method and apparatus for exposing photoresists using programmable masks. Case's method increases imaging resolution to provide fully dense integrated circuit patterns made of very small features on photoresist-coated silicon wafers by optical lithography.
The patent publication to Chen et al. (2004/0152011) provides for a reversible photobleachable materials based on nano-sized semiconductor particles and their optical applications, wherein the applications include reversible contrast enhancement layer (R-CEL) in optical lithography, lithography mask inspection and writing and optical storage technologies.
Whatever the precise merits, features, and advantages of the above cited references, none of them achieves or fulfills the purposes of the present invention.